Reference estimator

MM to Carat & Ratti.

Enter a gemstone’s length, breadth, and depth to estimate its weight. This is an estimate only—an independent scale or certificate is required for an exact weight.

Stone details

Estimated weight

Enter all three dimensions to calculate.

— ct

— ratti

Uses the selected stone’s relative density and a shape factor. Ratti is shown using the selected standard; ratti is not universally standardised.